One-way clutch



Patented Oct. 2, 1945 Application March 19, 1943, Serial No. 479,695

s claims. (c1. isz-45.1)

'I'his invention relates to a one-way clutch and 4 more particularly toa, clutch employing eccentric grippers and so designed thatthe gripperswill engage quickly under all conditions of operation.

Clutches have heretoforev been proposed employing eccentricvgripperswhich tilt in one direction to engage and in the other direction to'disengage. A great deal of dimculty has been encountered, however, inconstructing such clutches so that they will engagequickly under allconditions of operation with a minimum of lost motion and so that all ofthe grippers will engage uniformly. It is one of the objects of thepresent invention to provide a one-.way clutch in which thesedifiiculties are overcome.

It is another object of the invention to provide a one-way clutch inwhich the grippers are urged Figure 1, are of unequal size. yLine lvlintersects outer race l at the point where gripper lIl and i race I0contact. However, vthe centrifugal force on the sprag will beapproximately balanced about the pressure line il due to the fact thatthe opposite portions have unequal radii of gyration, having theirrespective centers of gravity at different distances from the axis I9.

into engaged position in response to centrifugal force thereon. Y

A further object of the invention is to provide a one-way clutch inwhich the grippers are urged into engagement in response to centrifugalforce and further in response to an accelerating or decelerating torcein either direction ci rotation.

The above and other objectsand advantages of the invention will beapparent from the following description, when read in connection withthe accompanying drawing, in which:

Figure 1 is a partial transverse section of a one-way clutch embodyingthe invention; and

Figure 2 is a similar view of another construction.

The one-way clutch of Figure 1 connects an outer cylindrical race l0 toan inner cylindrical race Il and includes a cage having spaced bars I2and -li leaving an. opening in the circumference of the cage between thebars. In this opening there is mounted a tiltable sprag or gripper Ilhaving flat sides and arcuate ends curved about spaced centers il andit. It will be noted that the centers are spaced along a line lying atan angle to the center line of the gripper and are arrangedsymmetrically with respect to the 'center of the gripper indicated atI'I, ignoring the counterweight 2l which will be explained later.symmetrical sprags' of the type so far described are known in the artand in such sprags the centrifugal force is balanced so that there islittle tendency to tilt the gripper' either into or out of engagement.It will be noted that centrifugal force acts in the direction of a .lineIl from the center point I9 and the center of the sprag I1. A line fromcenter l0 passing through the center point il to the outer arcuatesurface will divide vthe sprag into two portions which as seen invReferring to Figure 1. stillignoring counterweight 25, the center ofgravity of the leftportion of the sprag is indicated at 2l and thecenter of gravity of the right portion of the sprag is indicated at 22.The respective centers of gyration of the left and right halves areindicated at 23 and 24. From an examination of this figure,

' it will be readily seen that although the predominant mass of thespraglies to the left of the pressure line il, the centrifugal eiect onthe twol vsides will be approximately balanced because the center ofgravity and center of gyration of the right side lie at a greater radiusfrom the axis il.

In order to 'make the sprag responsive to centrifugal force according tothe present invention, it is unbalanced about the pressure line 'I8 sothat centrifugal force will tend to tilt it into a position to engagethe races. As shown in Figure l, this is accomplished by attaching aweight 25 to one side ofthe sprag, the weight preferably being arrangedas shown adjacent the outer race. The addition of this weight shifts thecenter of gravity of the sprag to a point 2l to the right of thepressure line Il and shifts the center of gravity of the right side to apoint 21. with this weight added, the sprag tends to tiltcounterciockwise under the influence of centrifugal forceinto a positionengaging the races il and ll. I

Each of the cross bars i3 is preferably provided with a spring 2l shownas comprising a clockwise. It will further be noted that the cross barI3 engages the sprag below vits main center of gravity while the crossbar i2 engages the sprag above its main center of gravity.. Thus theSpra is constantly urged toward engaged position by the spring 28 andwill be urged into engagement by the cross bars in response toaccelera'tlng or decelerating forces.

Considering that the cage is being accelerated in a' clockwisedirection, the. inertia of the sprag tends to cause it to move moreslowly than the cage so that the cross har i3 will engage the #D118 onitsy left side below center and tend to Thus 2 tilt it cmmterclockwise.Similarly, acceleration of the cage in a counterclockwise directionwillv cause the cross bar I2 to-engage the spragabove its center to tiltit into engaged position. Deceleration oi the cage clockwise will havethe same eect as acceleration coimterclockwise and vice versa, so thatthe sprag will be urged into engagement in to acceleration ordeceleration in either direction This eect added to the centrifugalaction on the sprag insures that itA will engage the races quickly-under .all conditions and since each sprag is acted on uniiormly byacceleration and centrifugal forces ali of the sprags in an assemblywill engage evenly.

Figure 2 illustrates an alternative construction oi' the sprag orgripper, the other parts in this iigure corresponding to-like parts inFigure l.

being designated by the same reference numerals.

The sprag or gripper of Figure 2 has nat sides 3| connected by an outerarcuate surface 32 curved about a center It and an inner arcuate 3l andare spaced along a line lying at an angle to the center line oi thegripper'and who mid point between theA centers lies `at one side of thecenter line oiethe gripper. The pressure surface Il curved about acenter 8S. 'me centers line of this sprag connecting its point of'con'-tact with-the outer race to the axisot the races is indicated at anddivides the sprag insuch a way that the maior portion of its mass lieson its right side. Also, the center of. gravity o! the spi-ag shown atIl lies to the right of the pressure linell and sincethe center orgravity ot the right side of the sprag at Slis at a greater radius thanthe center of gravity of its left side at V3i, the spragwill tend totilt counterclockwise ino' engagement with the races in to centrifugalforce.,y This construction, therefore,

operates in the same manner as that shown in Figure ibut eliminates thenecessity for external weights on thesprags and substantially simpllilesthe construction.

while two embodiments or the invention haveBeenshownanddescrlbedindetaiLitwillbe that these are illustrative onlyand notintended as a deiinition of the scope of tl''xlek'jixnre'ntion.'`reference being had for this purto the appended claims.

wnstisclauned is:

:1.1. one-way clutch comprising inner and outer coaxial races andgrippers mounted between the races: having substantially iiat parallelsidesandarcuateendscurvedaboutcenters spaced di'erent distances from thecenters of the grippers, the grippers being tiltable in one.directiontoconnecttheracesandintheother assenso o direction toccnnectthel'races under the action spaced dierent distances from the' centersoi the grippers along lines at an' angle to the center lines of thegrippers respectively, the mid point of each of the lines between thecenters closer to one side of the gripper than to the other and one ofsaid centers lying substannaliy on the center line of the gripper.

3. A one-way clutch comprising inner and outer coaxial races, a 'cagebetween the races formed with circumi'erentially spaced cross barsdeilning a sexies of openings, tiltable grippers `mounted in theopenings tiltable to one position in which 'they engage the races and toanother pontion in which they disensage the races, said slippers beingso balanced that they tend to tilt into engagement in response tocentrifugal torce',

and thelcross bars on the cage engaging the grippero at diiterent radialpositions on their oppositesides to urge them into engagement with thelraces in response to either an accelerating or iecelerating force;

LA one-way clutch comprising inner and outer coaxial races, a cagebetweenthe races formed-with cimumi'erentially spaced cross bars-cleiining a series o! openings, tiltable grippers mounted intheopenings tiltable to one position in which they engage the races andto another position in which they e the lacca-said srippers ybeing sobalances thatthey tend to tutintoengagement in response to centrifugali'orce,

Y the cross bars on the cage engaging the grippers at radial positionson their opposite sides to urge. themfinto engagement with the racesinresponse to either an accelerating or de- A celerating force, andspringscarried by certain ot theel-os bars the slippers to rse them intoengagement with the races.

5. A one-way clutch comprising inner and outer coaxial races. a cageVbetween the races f formed with circumferentiallyspaced cross barsdirection to disconnect-the races and being sobalancedthatamajorityoitheirmassliesonme Ysideotlinesextendingbetweentheirrespeetive points of contact withtheouter rsceand the axisof-theracessothattheitendtotiltina or deceleratingtorce.'

detlninga series o i openings', 'tiltable grippcrs mounted in theopeningstiltable to one position in which they engage the races and ,toanother position in which they diseugage the races, each of thevsnippers having flat .parallel sides and arcuate ends curved aboutcenters spaced eccentrically different distances from the center o! thegripper, andthe crossbarsonthe cage the gripper# at diilerent radialpositions on their opposite sides to urge them into engagement with theraces in response to either an accelerating

